For safety reasons, it has been desirable to fasten truck wheel lug nuts with power tools (e.g., pneumatic drivers) that can deliver higher torques than have been obtainable by hand. As a result of this need for power assistance in tightening, a power driver is required any time a tire needs to be removed or the tightness of a nut needs to be checked or adjusted. This means that such work must be done in a service center, or, in the event of a roadside emergency, by either a roadside service vehicle or an on-board power driver if available. However, roadside service is expensive and time-consuming, and sufficiently powerful on-board equipment is expensive. A need exists for a lower cost alternative.
The lower cost alternatives are often manual tools. However, the use of manual tools on truck wheels is complicated by the fact that most truck wheels except those on the front end have lug nuts that are recessed as much as a foot from the outer edge of the tire. If a conventional wrench or breaker bar is used with an extension enabling access to these lugs, not only does the user have to support the weight of the wrench, he also has to balance his rotational force to keep from twisting the tool off the lug nut. The present invention anchors the tool and balances the forces so that only the modest weight of the tool need be supported manually.
The present invention is a tool for tightening or loosening a fastener, the tool being anchored against reactive force to a nearby fastener or stud, and utilizing a screw to pull or push a wrench handle against the anchor. The screw increases the hand torque applied to it to levels comparable to a power driver. Further, the tool is shaped to permit its use in the tight space found in the annular recess surrounding the hubs of most truck wheels. Principal objects of the invention are to provide: a) a hand tool capable of generating the very high torques needed to adjust truck wheel lug nuts with relatively low cost, weight, and space requirements; b) a tool that can be used on a variety of lug nut configurations including both recessed nuts (such as are typically found on rear axle wheels of tractor-trailer trucks) as well as easily-accessible nuts (such as those usually found on the front wheels of truck tractors); c) a tool designed so that the active and reactive forces are collinear and the moments coaxial so that the user does not have to resist applied forces during use of the tool to keep it in place; and d) a tool designed to keep internal stresses that would reduce efficiency due to friction to a low level.